[PATCH] drm/amd/amdgpu: Add tracepoint for DMA page mapping (v2)

[tom.stdenis@xxxxxxx (Tom St Denis)]

This helps map DMA addresses back to physical addresses.

Signed-off-by: Tom St Denis <tom.stdenis at amd.com>

(v2):  Added tracepoints for USERPTR, SG mappings, and
     SWIOTBL mappings.  Reformatted trace call perform
     PCI decoding internal to the trace.
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_trace.h | 28 +++++++++++++++++++++++++
 drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c   | 35 ++++++++++++++++++++++++-------
 2 files changed, 56 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_trace.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_trace.h
index 509f7a63d40c..3e0f1885a379 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_trace.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_trace.h
@@ -14,6 +14,34 @@
 #define AMDGPU_JOB_GET_TIMELINE_NAME(job) \
 	 job->base.s_fence->finished.ops->get_timeline_name(&job->base.s_fence->finished)
 
+TRACE_EVENT(amdgpu_ttm_tt_populate,
+	    TP_PROTO(struct amdgpu_device *adev, uint64_t dma_address, uint64_t phys_address),
+	    TP_ARGS(adev, dma_address, phys_address),
+	    TP_STRUCT__entry(
+				__field(uint16_t, domain)
+				__field(uint8_t, bus)
+				__field(uint8_t, slot)
+				__field(uint8_t, func)
+				__field(uint64_t, dma)
+				__field(uint64_t, phys)
+			    ),
+	    TP_fast_assign(
+			   __entry->domain = pci_domain_nr(adev->pdev->bus);
+			   __entry->bus = adev->pdev->bus->number;
+			   __entry->slot = PCI_SLOT(adev->pdev->devfn);
+			   __entry->func = PCI_FUNC(adev->pdev->devfn);
+			   __entry->dma = dma_address;
+			   __entry->phys = phys_address;
+			   ),
+	    TP_printk("%04x:%02x:%02x.%x: 0x%llx => 0x%llx",
+		      (unsigned)__entry->domain,
+		      (unsigned)__entry->bus,
+		      (unsigned)__entry->slot,
+		      (unsigned)__entry->func,
+		      (unsigned long long)__entry->dma,
+		      (unsigned long long)__entry->phys)
+);
+
 TRACE_EVENT(amdgpu_mm_rreg,
 	    TP_PROTO(unsigned did, uint32_t reg, uint32_t value),
 	    TP_ARGS(did, reg, value),
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
index 8da59d212b3b..7857fc581342 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
@@ -43,6 +43,7 @@
 #include <linux/pagemap.h>
 #include <linux/debugfs.h>
 #include "amdgpu.h"
+#include "amdgpu_trace.h"
 #include "bif/bif_4_1_d.h"
 
 #define DRM_FILE_PAGE_OFFSET (0x100000000ULL >> PAGE_SHIFT)
@@ -667,7 +668,7 @@ static int amdgpu_ttm_tt_pin_userptr(struct ttm_tt *ttm)
 {
 	struct amdgpu_device *adev = amdgpu_ttm_adev(ttm->bdev);
 	struct amdgpu_ttm_tt *gtt = (void *)ttm;
-	unsigned nents;
+	unsigned i, nents;
 	int r;
 
 	int write = !(gtt->userflags & AMDGPU_GEM_USERPTR_READONLY);
@@ -688,6 +689,15 @@ static int amdgpu_ttm_tt_pin_userptr(struct ttm_tt *ttm)
 	drm_prime_sg_to_page_addr_arrays(ttm->sg, ttm->pages,
 					 gtt->ttm.dma_address, ttm->num_pages);
 
+	if (unlikely(trace_amdgpu_ttm_tt_populate_enabled())) {
+		for (i = 0; i < ttm->num_pages; i++) {
+			trace_amdgpu_ttm_tt_populate(
+				adev,
+				gtt->ttm.dma_address[i],
+				page_to_phys(ttm->pages[i]));
+		}
+	}
+
 	return 0;
 
 release_sg:
@@ -892,7 +902,7 @@ static struct ttm_tt *amdgpu_ttm_tt_create(struct ttm_bo_device *bdev,
 
 static int amdgpu_ttm_tt_populate(struct ttm_tt *ttm)
 {
-	struct amdgpu_device *adev;
+	struct amdgpu_device *adev = amdgpu_ttm_adev(ttm->bdev);
 	struct amdgpu_ttm_tt *gtt = (void *)ttm;
 	unsigned i;
 	int r;
@@ -915,14 +925,14 @@ static int amdgpu_ttm_tt_populate(struct ttm_tt *ttm)
 		drm_prime_sg_to_page_addr_arrays(ttm->sg, ttm->pages,
 						 gtt->ttm.dma_address, ttm->num_pages);
 		ttm->state = tt_unbound;
-		return 0;
+		r = 0;
+		goto trace_mappings;
 	}
 
-	adev = amdgpu_ttm_adev(ttm->bdev);
-
 #ifdef CONFIG_SWIOTLB
 	if (swiotlb_nr_tbl()) {
-		return ttm_dma_populate(&gtt->ttm, adev->dev);
+		r = ttm_dma_populate(&gtt->ttm, adev->dev);
+		goto trace_mappings;
 	}
 #endif
 
@@ -945,7 +955,18 @@ static int amdgpu_ttm_tt_populate(struct ttm_tt *ttm)
 			return -EFAULT;
 		}
 	}
-	return 0;
+
+	r = 0;
+trace_mappings:
+	if (!r && unlikely(trace_amdgpu_ttm_tt_populate_enabled())) {
+		for (i = 0; i < ttm->num_pages; i++) {
+			trace_amdgpu_ttm_tt_populate(
+				adev,
+				gtt->ttm.dma_address[i],
+				page_to_phys(ttm->pages[i]));
+		}
+	}
+	return r;
 }
 
 static void amdgpu_ttm_tt_unpopulate(struct ttm_tt *ttm)
-- 
2.12.0